Directly driven, low-speed permanent-magnet generators for wind power applications

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Lampola, Petri
dc.date.accessioned 2012-02-10T09:50:52Z
dc.date.available 2012-02-10T09:50:52Z
dc.date.issued 2000-05-29
dc.identifier.isbn 951-22-5692-4
dc.identifier.issn 0001-6845
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2268
dc.description.abstract The rotor of a typical wind turbine rotates at a speed of 20-200 rpm. In conventional wind power plants the generator is coupled to the turbine via a gear so that it can typically rotate at a speed of 1000 or 1500 rpm. The wind power plant can be simplified by eliminating the gear and by using a low-speed generator, the rotor of which rotates at the same speed as the rotor of the turbine. The hypothesis in this work is that the typical generator-gear solution in the wind power plant can be replaced by a low-speed PM synchronous generator. This thesis deals with the electromagnetic design and the optimisation of two types of low-speed generators for gearless wind turbines. The generators designed are radial-flux permanent-magnet synchronous machines excited by NdFeB magnets. The machines have different kinds of stator windings. The first machine has a conventional three-phase, diamond winding. The second machine has a three-phase, unconventional single-coil winding consisting of coils which are placed in slots around every second tooth. The electromagnetic optimisation of the machine is done by the finite element method and by a genetic algorithm combined with the finite element method. The rated powers of the machines optimised are 500 kW, 10 kW and 5.5 kW. Two prototype machines were built and tested. The optimisation of the machines shows that the cost of active materials is smaller and the pull-out torque per the cost of active materials higher in the conventional machines than in the single-coil winding machines. The torque ripple can be reduced to a low level by choosing a suitable magnet and stator slot shape in both the designs. The demagnetisation of permanent magnets is easier to avoid in the single-coil winding machines than in the conventional designs. The investigation of various rotor designs shows that the rotor equipped with curved surface-mounted magnets has various advantages compared with the other rotor designs, for instance pole shoe versions. The analysis of the machines also shows that the load capacity of the machine is lower in a diode rectifier load than that when connected directly to a sinusoidal grid. According to the analysis, a typical generator-gear solution of the wind power plant can be replaced by a multipole radial-flux PM synchronous machine. The conventional diamond winding machine is a better choice for the design of a directly driven wind turbine generator but the single-coil winding machine is also suitable because of its simplicity. en
dc.format.extent 62, [94]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Acta polytechnica Scandinavica. El en
dc.relation.ispartofseries 101 en
dc.relation.haspart Lampola, P., Saari, J., Perho, J. 1997: Electromagnetic Design of a Low-Speed Surface-Mounted Permanent-Magnet Wind Generator, Electromotion, 1997, Vol. 4, No. 4, pp. 147-154.
dc.relation.haspart Lampola, P., Perho, J., Väänänen, J. 1996: Analysis of a Low-Speed Permanent-Magnet Wind Generator Connected to a Frequency Converter, In Proceedings of the International Conference on Electrical Machines (ICEM'96), Vigo, Spain, 10-12 September, 1996, Vol. 2, pp. 393-398.
dc.relation.haspart Lampola, P., Perho, J., Väänänen, J. 1996: Analysis of a Low-Speed Permanent-Magnet Wind Generator, In Proceedings of the European Union Wind Energy Conference and Exhibition, Göteborg, Sweden, 20-24 May, 1996, pp. 500-503.
dc.relation.haspart Lampola, P. 1996: Losses in a Directly Driven, Low-Speed Permanent-Magnet Wind Generator, In Proceedings of the Nordic Research Symposium on Energy Efficient Electric Motors and Drives, Skagen, Denmark, 12-16 August, 1996, pp. 358-364.
dc.relation.haspart Lampola, P. 1999: Optimisation of Low-Speed Permanent-Magnet Synchronous Machines with Different Rotor Designs, Electromotion, 1999, Vol. 6, No. 4, pp. 147-159.
dc.relation.haspart Lampola, P., Tellinen, J. 1997: Directly Driven Permanent-Magnet Generator for Wind Power Applications, In Proceedings of the European Wind Energy Conference (EWEC'97), Dublin, Ireland, 5-9 October, 1997, pp. 698-701.
dc.relation.haspart Lampola, P. 1998: Electromagnetic Design of an Unconventional Directly Driven Permanent-Magnet Wind Generator, In Proceedings of the International Conference on Electrical Machines (ICEM'98), Istanbul, Turkey, 2-4 September, 1998, Vol. 3, pp. 1705-1710.
dc.relation.haspart Tellinen, J., Lampola, P., Jokinen, T. 1996: Low-Speed Permanent Magnet Machine with High-Torque Capacity, In Proceedings of the Second International Scientific and Technical Conference on Unconventional Electromechanical and Electrotechnical Systems (UEES'96), Szczecin, Poland, 15-17 December, 1996, Vol. 2, pp. 377-382.
dc.relation.haspart Lampola, P. 1999: Low-Speed Permanent-Magnet Generators for Gearless Wind Turbines, Helsinki University of Technology, Laboratory of Electromechanics, Report, No. 62, Espoo, Finland, 2000, 24 p. Submitted to European Transactions on Electrical Power (ETEP) July 12, 1999.
dc.relation.haspart Lampola, P. 1999: Optimisation of a Directly Driven, Low-Speed Permanent-Magnet Wind Generator, In Proceedings of the Fourth International Scientific and Technical Conference on Unconventional Electromechanical and Electrotechnical Systems (UEES'98), St. Petersburg, Russia, 21-24 June, 1999, Vol. 3, pp. 1147-1152.
dc.subject.other Electrical engineering en
dc.subject.other Energy en
dc.title Directly driven, low-speed permanent-magnet generators for wind power applications en
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Electrical and Communications Engineering en
dc.contributor.department Sähkö- ja tietoliikennetekniikan osasto fi
dc.subject.keyword permanent-magnet generator en
dc.subject.keyword gearless wind turbine en
dc.subject.keyword directly driven en
dc.subject.keyword low speed en
dc.identifier.urn urn:nbn:fi:tkk-002389
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Laboratory of Electromechanics en
dc.contributor.lab Sähkömekaniikan laboratorio fi


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